The objective of the research described in this application is to study the role of the homotypical neocortex in some higher functions of the brain; namely, directed visual attention, and visually guided movements. Experiments will be made in waking, behaving monkeys trained to execute tasks requiring visual attention, or accurate visually guided movements while, simultaneously, recordings are made of the action potentials of single cortical neurons. The areas to be studied are the posterior parietal cortex, and the premotor areas of the frontal lobe. Combined anatomical experiments will be made with transport labelling methods, to define local zones of cortex emitting and receiving commissural and ipsilateral cortico-cortical systems of fibers, so that the macrocolumns studied during microelectrode penetrations can be defined both in terms of the functional properties of their neurons, and their extrinsic connections. All observations will be synthesized in terms of the action of populations of neurons, and used synthetically to make inferences concerning the intrinsic function of the neocortex, and of distributed systems of the cerebrum.